1. FIELD OF THE INVENTION
The present invention relates to the field of exercising devices and more particularly to an exercising device for measuring human breath inhalation rates and promoting proper breathing especially for persons who have breathing problems.
2. DESCRIPTION OF THE PRIOR ART
There has been a need in the medical field for devices which can measure the ability of patients to inhale, as well as to provide incentives for patients to fully develop or rebuild their respiratory systems. These patients may include post surgical, inactive, obese, and geriatric patients who need to increase their lung capacity. To encourage these patients to overcome their pain or discomfort in breathing deeply, an incentive measuring device which encourages a proper type of breathing is needed.
It is believed that the most beneficial results of breathing occur when there is a slow, sustained and deep inhalation of air into the lungs. It is with that kind of inspiration that there is the maximum expansion of the lungs and the optimal conditions for gaseous exchange at the aveolar sites, or air cells, of the lungs. A sustained, steady, deep inhalation of laminar flow is preferred for patients rather than a short, rapid, nongradual inhalation effort which causes turbulent flow.
The device disclosed in U.S. Pat. No. 4,060,074 issued Nov. 29, 1977, is intended to provide some of the features required for achieving the desired results. The principal device described in that patent has three adjacent chambers, each containing a ball, and an air passageway common to all three chambers. In operation when a person inhales through the device, air flows through all chambers and the air passageway and if a minimum flow rate is exceeded the balls will be raised sequentially to the tops of the chambers.
One of the problems with the prior art device is that a ball is not actuated at all until there is a minimum flow of air through the whole device. However, it has been found in this device that the lowest accurate measurable flow rate when used in its normal position is approximately 600 cc/sec, which is greater than most respiratory patients can accomplish at the beginning of their therapy and greater than the optimal therapeutic rates for these patients. Thus there is a need for an incentive inhalation device which can accurately measure the preferred laminar inhalation rates and can provide patients with a visible readout of their efforts in that range of air flow.
A further problem with the prior art device is that although air is drawn into the whole device, the air flow may become restricted during its operation. The air passageway which is common to all the chambers of the device and through which air is withdrawn from the entire system is considerably smaller in cross-sectional area than the chambers and may cause an impedance to the air flow. Additionally, when the precalibrated flow rate has been achieved, each of the balls rises sequentially in its chamber and closes off the air exit at the top. This causes a sudden restriction in the air flow through each chamber as it is closed off, which interrupts the inhalation effort of the user attempting to achieve a smooth air flow. A further negative effect of this feature of operation is that as subsequent balls are raised, a patient is forced to expend unnecessary energy to keep the previously raised balls suspended.
By virtue of the construction of this multi-chambered device, and the fact that the air flow is being drawn through each chamber concurrently until the first chambers are closed, it is expected that the process of calibration is quite difficult, especially at the low laminar flow rates.
A further disadvantage of the prior art device of U.S. Pat. No. 4,060,074 is that it does not provide any indication of inhalation rate until the first ball is raised. At that point a user can see only that he or she has exceeded the specified rate and cannot be certain of the exact inhalation rate of air flow achieved. Then only a very limited number and range of rates can be measured. Thus there is a need for an inhalation device that can provide a simple but accurate readout of small variations in air flow, especially at the preferred low inhalation laminar flow rates. There is also a need for an inhalation meter for healthier patients which can accurately measure a wider range of inspiration rates and which has very little air flow restriction throughout its system. The present invention provides a solution to these problems and overcomes the disadvantages of the prior art devices by providing an inhalation measurement device with a simple readout and sensitivity over a wide range of inhalation rates but with minimum restriction on the air flow to the user.